Art, yeah, Poland (Ohio) isn't all that far. I'm tempted to pay a visit myself assuming he wouldn't mind. Seems like the type of guy you can learn a lot from.
Sas, I was wondering about how you would root prune the trees in the barrel also. I suppose in a worst case scenario you could cut the top third off and pull the tree out. That would still leave you with a decent-sized container for a smaller tree.